Dozens of police were searching the company’s offices in Laval, western France, as well as its factory in nearby Craon which was the source of the tainted milk. Lactalis has recalled baby milk from 83 countries, with anger growing after it emerged that the company’s own tests had discovered salmonella at the Craon site in August and November.

The company did not report the findings and it says it had no legal obligation to do so because it had not detected salmonella in its products.

The contamination, found in a dehydration tower used to reduce milk, was not revealed to the public until December. At least 37 babies in France are known to have fallen sick and another in Spain, while Greece has also seen one unconfirmed case.

A source close to the probe said magistrates and 70 police were raiding Lactalis sites on Wednesday.